diff --git a/cores/arduino/Print.cpp b/cores/arduino/Print.cpp
index e541a6c..711251c 100755
--- a/cores/arduino/Print.cpp
+++ b/cores/arduino/Print.cpp
@@ -226,6 +226,9 @@ size_t Print::printFloat(double number, uint8_t digits)
 { 
   size_t n = 0;
   
+  if (isnan(number)) return print("nan");
+  if (isinf(number)) return print("inf");
+  
   // Handle negative numbers
   if (number < 0.0)
   {
diff --git a/cores/arduino/Print.h b/cores/arduino/Print.h
index 1af6b72..dc76150 100755
--- a/cores/arduino/Print.h
+++ b/cores/arduino/Print.h
@@ -46,7 +46,10 @@ class Print
     void clearWriteError() { setWriteError(0); }
   
     virtual size_t write(uint8_t) = 0;
-    size_t write(const char *str) { return write((const uint8_t *)str, strlen(str)); }
+    size_t write(const char *str) {
+      if (str == NULL) return 0;
+      return write((const uint8_t *)str, strlen(str));
+    }
     virtual size_t write(const uint8_t *buffer, size_t size);
     
     size_t print(const __FlashStringHelper *);
diff --git a/cores/arduino/USBAPI.h b/cores/arduino/USBAPI.h
index d5abdb6..eb2e593 100644
--- a/cores/arduino/USBAPI.h
+++ b/cores/arduino/USBAPI.h
@@ -39,6 +39,7 @@ public:
 	virtual int read(void);
 	virtual void flush(void);
 	virtual size_t write(uint8_t);
+	using Print::write; // pull in write(str) and write(buf, size) from Print
 	operator bool();
 };
 extern Serial_ Serial;
diff --git a/cores/arduino/WInterrupts.c b/cores/arduino/WInterrupts.c
index 8f3ec84..62efc9c 100644
--- a/cores/arduino/WInterrupts.c
+++ b/cores/arduino/WInterrupts.c
@@ -59,6 +59,14 @@ void attachInterrupt(uint8_t interruptNum, void (*userFunc)(void), int mode) {
 		EICRA = (EICRA & ~((1<<ISC10) | (1<<ISC11))) | (mode << ISC10);
 		EIMSK |= (1<<INT1);
 		break;	
+    case 2:
+        EICRA = (EICRA & ~((1<<ISC20) | (1<<ISC21))) | (mode << ISC20);
+        EIMSK |= (1<<INT2);
+        break;
+    case 3:
+        EICRA = (EICRA & ~((1<<ISC30) | (1<<ISC31))) | (mode << ISC30);
+        EIMSK |= (1<<INT3);
+        break;
 #elif defined(EICRA) && defined(EICRB) && defined(EIMSK)
     case 2:
       EICRA = (EICRA & ~((1 << ISC00) | (1 << ISC01))) | (mode << ISC00);
@@ -147,12 +155,18 @@ void detachInterrupt(uint8_t interruptNum) {
     // ATmega8.  There, INT0 is 6 and INT1 is 7.)
     switch (interruptNum) {
 #if defined(__AVR_ATmega32U4__)
-	case 0:
-		EIMSK &= ~(1<<INT0);
-		break;
-	case 1:
-		EIMSK &= ~(1<<INT1);
-		break;		
+    case 0:
+        EIMSK &= ~(1<<INT0);
+        break;
+    case 1:
+        EIMSK &= ~(1<<INT1);
+        break;
+    case 2:
+        EIMSK &= ~(1<<INT2);
+        break;
+    case 3:
+        EIMSK &= ~(1<<INT3);
+        break;		
 #elif defined(EICRA) && defined(EICRB) && defined(EIMSK)
     case 2:
       EIMSK &= ~(1 << INT0);
@@ -226,6 +240,16 @@ SIGNAL(INT1_vect) {
 		intFunc[EXTERNAL_INT_1]();
 }
 
+SIGNAL(INT2_vect) {
+    if(intFunc[EXTERNAL_INT_2])
+		intFunc[EXTERNAL_INT_2]();
+}
+
+SIGNAL(INT3_vect) {
+    if(intFunc[EXTERNAL_INT_3])
+		intFunc[EXTERNAL_INT_3]();
+}
+
 #elif defined(EICRA) && defined(EICRB)
 
 SIGNAL(INT0_vect) {
diff --git a/cores/arduino/wiring_private.h b/cores/arduino/wiring_private.h
index f0ceb0c..026ce1a 100755
--- a/cores/arduino/wiring_private.h
+++ b/cores/arduino/wiring_private.h
@@ -56,6 +56,8 @@ extern "C"{
 #define EXTERNAL_NUM_INTERRUPTS 8
 #elif defined(__AVR_ATmega1284P__) 
 #define EXTERNAL_NUM_INTERRUPTS 3
+#elif defined(__AVR_ATmega32U4__)
+#define EXTERNAL_NUM_INTERRUPTS 4
 #else
 #define EXTERNAL_NUM_INTERRUPTS 2
 #endif
diff --git a/libraries/SD/utility/Sd2PinMap.h b/libraries/SD/utility/Sd2PinMap.h
index 4bd75a3..1c76dd3 100644
--- a/libraries/SD/utility/Sd2PinMap.h
+++ b/libraries/SD/utility/Sd2PinMap.h
@@ -166,44 +166,43 @@ static const pin_map_t digitalPinMap[] = {
 };
 //------------------------------------------------------------------------------
 #elif defined(__AVR_ATmega32U4__)
-// Teensy 2.0
+// Leonardo
 
 // Two Wire (aka I2C) ports
-uint8_t const SDA_PIN = 6;
-uint8_t const SCL_PIN = 5;
+uint8_t const SDA_PIN = 2;
+uint8_t const SCL_PIN = 3;
 
 // SPI port
-uint8_t const SS_PIN = 0;
-uint8_t const MOSI_PIN = 2;
-uint8_t const MISO_PIN = 3;
-uint8_t const SCK_PIN = 1;
+uint8_t const SS_PIN = 17;
+uint8_t const MOSI_PIN = 16;
+uint8_t const MISO_PIN = 14;
+uint8_t const SCK_PIN = 15;
 
 static const pin_map_t digitalPinMap[] = {
-  {&DDRB, &PINB, &PORTB, 0},  // B0  0
-  {&DDRB, &PINB, &PORTB, 1},  // B1  1
-  {&DDRB, &PINB, &PORTB, 2},  // B2  2
-  {&DDRB, &PINB, &PORTB, 3},  // B3  3
-  {&DDRB, &PINB, &PORTB, 7},  // B7  4
-  {&DDRD, &PIND, &PORTD, 0},  // D0  5
-  {&DDRD, &PIND, &PORTD, 1},  // D1  6
-  {&DDRD, &PIND, &PORTD, 2},  // D2  7
-  {&DDRD, &PIND, &PORTD, 3},  // D3  8
-  {&DDRC, &PINC, &PORTC, 6},  // C6  9
-  {&DDRC, &PINC, &PORTC, 7},  // C7 10
-  {&DDRD, &PIND, &PORTD, 6},  // D6 11
-  {&DDRD, &PIND, &PORTD, 7},  // D7 12
-  {&DDRB, &PINB, &PORTB, 4},  // B4 13
-  {&DDRB, &PINB, &PORTB, 5},  // B5 14
-  {&DDRB, &PINB, &PORTB, 6},  // B6 15
-  {&DDRF, &PINF, &PORTF, 7},  // F7 16
-  {&DDRF, &PINF, &PORTF, 6},  // F6 17
-  {&DDRF, &PINF, &PORTF, 5},  // F5 18
-  {&DDRF, &PINF, &PORTF, 4},  // F4 19
-  {&DDRF, &PINF, &PORTF, 1},  // F1 20
-  {&DDRF, &PINF, &PORTF, 0},  // F0 21
-  {&DDRD, &PIND, &PORTD, 4},  // D4 22
-  {&DDRD, &PIND, &PORTD, 5},  // D5 23
-  {&DDRE, &PINE, &PORTE, 6}   // E6 24
+  {&DDRD, &PIND, &PORTD, 2},  // D2  0
+  {&DDRD, &PIND, &PORTD, 3},  // D3  1
+  {&DDRD, &PIND, &PORTD, 1},  // D1  2
+  {&DDRD, &PIND, &PORTD, 0},  // D0  3
+  {&DDRD, &PIND, &PORTD, 4},  // D4  4
+  {&DDRC, &PINC, &PORTC, 6},  // C6  5
+  {&DDRD, &PIND, &PORTD, 7},  // D7  6
+  {&DDRE, &PINE, &PORTE, 6},  // E6  7
+  {&DDRB, &PINB, &PORTB, 4},  // B4  8
+  {&DDRB, &PINB, &PORTB, 5},  // B5  9
+  {&DDRB, &PINB, &PORTB, 6},  // B6 10
+  {&DDRB, &PINB, &PORTB, 7},  // B7 11
+  {&DDRD, &PIND, &PORTD, 6},  // D6 12
+  {&DDRC, &PINC, &PORTC, 7},  // C7 13
+  {&DDRB, &PINB, &PORTB, 3},  // B3 14
+  {&DDRB, &PINB, &PORTB, 1},  // B1 15
+  {&DDRB, &PINB, &PORTB, 2},  // B2 16
+  {&DDRB, &PINB, &PORTB, 0},  // B0 17
+  {&DDRF, &PINF, &PORTF, 7},  // F7 18
+  {&DDRF, &PINF, &PORTF, 6},  // F6 19
+  {&DDRF, &PINF, &PORTF, 5},  // F5 20
+  {&DDRF, &PINF, &PORTF, 4},  // F4 21
+  {&DDRF, &PINF, &PORTF, 1},  // F1 22
+  {&DDRF, &PINF, &PORTF, 0},  // F0 23
 };
 //------------------------------------------------------------------------------
 #elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
diff --git a/libraries/SPI/SPI.cpp b/libraries/SPI/SPI.cpp
index 42915df..5e48073 100644
--- a/libraries/SPI/SPI.cpp
+++ b/libraries/SPI/SPI.cpp
@@ -14,27 +14,32 @@
 SPIClass SPI;
 
 void SPIClass::begin() {
-  // Set direction register for SCK and MOSI pin.
-  // MISO pin automatically overrides to INPUT.
+
+  // Set SS to high so a connected chip will be "deselected" by default
+  digitalWrite(SS, HIGH);
+
   // When the SS pin is set as OUTPUT, it can be used as
   // a general purpose output port (it doesn't influence
   // SPI operations).
-
-  pinMode(SCK, OUTPUT);
-  pinMode(MOSI, OUTPUT);
   pinMode(SS, OUTPUT);
-  
-  digitalWrite(SCK, LOW);
-  digitalWrite(MOSI, LOW);
-  digitalWrite(SS, HIGH);
 
-  // Warning: if the SS pin ever becomes a LOW INPUT then SPI 
-  // automatically switches to Slave, so the data direction of 
+  // Warning: if the SS pin ever becomes a LOW INPUT then SPI
+  // automatically switches to Slave, so the data direction of
   // the SS pin MUST be kept as OUTPUT.
   SPCR |= _BV(MSTR);
   SPCR |= _BV(SPE);
+
+  // Set direction register for SCK and MOSI pin.
+  // MISO pin automatically overrides to INPUT.
+  // By doing this AFTER enabling SPI, we avoid accidentally
+  // clocking in a single bit since the lines go directly
+  // from "input" to SPI control.  
+  // http://code.google.com/p/arduino/issues/detail?id=888
+  pinMode(SCK, OUTPUT);
+  pinMode(MOSI, OUTPUT);
 }
 
+
 void SPIClass::end() {
   SPCR &= ~_BV(SPE);
 }
diff --git a/libraries/SoftwareSerial/examples/SoftwareSerialExample/SoftwareSerialExample.ino b/libraries/SoftwareSerial/examples/SoftwareSerialExample/SoftwareSerialExample.ino
index 69bcc01..6101bb1 100644
--- a/libraries/SoftwareSerial/examples/SoftwareSerialExample/SoftwareSerialExample.ino
+++ b/libraries/SoftwareSerial/examples/SoftwareSerialExample/SoftwareSerialExample.ino
@@ -5,11 +5,20 @@
  Receives from software serial, sends to hardware serial.
  
  The circuit: 
- * RX is digital pin 2 (connect to TX of other device)
- * TX is digital pin 3 (connect to RX of other device)
+ * RX is digital pin 10 (connect to TX of other device)
+ * TX is digital pin 11 (connect to RX of other device)
+ 
+ Note:
+ Not all pins on the Mega and Mega 2560 support change interrupts, 
+ so only the following can be used for RX: 
+ 10, 11, 12, 13, 50, 51, 52, 53, 62, 63, 64, 65, 66, 67, 68, 69
+ 
+ Not all pins on the Leonardo support change interrupts, 
+ so only the following can be used for RX: 
+ 8, 9, 10, 11, 14 (MISO), 15 (SCK), 16 (MOSI).
  
  created back in the mists of time
- modified 9 Apr 2012
+ modified 25 May 2012
  by Tom Igoe
  based on Mikal Hart's example
  
@@ -18,17 +27,17 @@
  */
 #include <SoftwareSerial.h>
 
-SoftwareSerial mySerial(2, 3); // RX, TX
+SoftwareSerial mySerial(10, 11); // RX, TX
 
 void setup()  
 {
- // Open serial communications and wait for port to open:
+  // Open serial communications and wait for port to open:
   Serial.begin(57600);
-   while (!Serial) {
+  while (!Serial) {
     ; // wait for serial port to connect. Needed for Leonardo only
   }
 
-  
+
   Serial.println("Goodnight moon!");
 
   // set the data rate for the SoftwareSerial port
@@ -43,3 +52,4 @@ void loop() // run over and over
   if (Serial.available())
     mySerial.write(Serial.read());
 }
+
diff --git a/libraries/SoftwareSerial/examples/TwoPortReceive/TwoPortReceive.ino b/libraries/SoftwareSerial/examples/TwoPortReceive/TwoPortReceive.ino
index d9f8f45..d607ee6 100644
--- a/libraries/SoftwareSerial/examples/TwoPortReceive/TwoPortReceive.ino
+++ b/libraries/SoftwareSerial/examples/TwoPortReceive/TwoPortReceive.ino
@@ -16,8 +16,17 @@
  * First serial device's TX attached to digital pin 2, RX to pin 3
  * Second serial device's TX attached to digital pin 4, RX to pin 5
  
+ Note:
+ Not all pins on the Mega and Mega 2560 support change interrupts, 
+ so only the following can be used for RX: 
+ 10, 11, 12, 13, 50, 51, 52, 53, 62, 63, 64, 65, 66, 67, 68, 69
+ 
+ Not all pins on the Leonardo support change interrupts, 
+ so only the following can be used for RX: 
+ 8, 9, 10, 11, 14 (MISO), 15 (SCK), 16 (MOSI).
+ 
  created 18 Apr. 2011
- modified 9 Apr 2012
+ modified 25 May 2012
  by Tom Igoe
  based on Mikal Hart's twoPortRXExample
  
@@ -26,11 +35,12 @@
  */
 
 #include <SoftwareSerial.h>
-// software serial #1: TX = digital pin 2, RX = digital pin 3
-SoftwareSerial portOne(2, 3);
+// software serial #1: TX = digital pin 10, RX = digital pin 11
+SoftwareSerial portOne(10,11);
 
-// software serial #2: TX = digital pin 4, RX = digital pin 5
-SoftwareSerial portTwo(4, 5);
+// software serial #2: TX = digital pin 8, RX = digital pin 9
+// on the Mega, use other pins instead, since 8 and 9 don't work on the Mega
+SoftwareSerial portTwo(8,9);
 
 void setup()
 {